With the popularity of minimally invasive medical procedures, catheter designers continue to revise and improve catheters for medical use, trying to build catheters that can articulate in mammalian subjects and perform the challenging functions demanded of minimally invasive procedures. Catheters for minimally invasive procedures need to bend at the distal tip and need to allow access through the catheter-body by instruments that perform the procedure. Catheters with steerable wires and proximal controls have been built and described. The challenge continues with these catheters to build a device that can better articulate to a site in the mammal and once at that site to position the tip properly for the procedure. The catheters also need to steer easily and to hold an articulated position once the correct angle of catheter bend is achieved. Along these lines, problems have continued in determining optimal place merits of the steering wires in the catheter. The goal is to convey the most effective tension to the distal tip through the steering wire, see e.g. U.S. Pat. No. 5,507,725 which describes placement of the steering wires in the catheter wall.
Another problem has been how to steer the wires so that the practitioner can position the catheter and still be able to control instruments that access the catheter to perform the procedure, see e.g. U.S. Pat. No. 5,656,030 for a description of a catheter with a complicated steering control mechanism. Catheters that articulate in a single direction using a pull wire have been described, see e.g. U.S. Pat. No. 6,783,510, but this catheter lacks the usefulness of a catheter that can articulate in more than one direction.
Particularly for performing catheter-based procedures at the heart, or other procedures where it is advantageous to have a steerable catheter, it would be desirable to have a catheter with a distal tip that can articulate in more than one direction in order to adjust the positioning of the catheter to the contours of the site, and a catheter that can be controlled easily, and accurately, while still providing the opportunity for instrument access through a central working lumen. The present invention overcomes some of the deficiencies in the current catheter art by providing the following invention.